Tertiary structure in E. coli tRNA Arg and tRNA Val

Abstract

300 MHz proton NMR has been used to demonstrate that both Escherichia coli tRNA A rg and tRNA V al 1 have a tertiary structure base pair between 4-thiouridine (s 4U) at position 8 and A at position 14. Formation of this s 4U 8-A 14 base pair leads to a very low field (14.8 ppm) resonance in the spectra of both molecules. When s 4U is converted to U the 14.8 resonance is replaced by a new resonance which appears at 14.3 ppm. The presence of the tertiary structure s 4U 8-A 14 base pair greatly constrains the folding of these tRNAs in solution.